kj
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| posted on 28/6/11 at 06:49 AM |
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ABS
Anyone know about or work for Renault, my wifes Clio has a problem with the ABS.
No warning lights and have checked the ABS ring on the drive shafts for damage and cleaned them up, no adjustment on the sensors, so as it has sensors
on both back and front how do i check and find out which one is at fault?
Its a 55 plate 1.2 model if that helps.
Think about it, think about it again and then do it.
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britishtrident
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| posted on 28/6/11 at 07:20 AM |
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An ABS fault without a warning lamp showing is almost unheard of unless some helpful previous owner has disable the lamp by removing the bulb.
You can check the sensor by connecting an oscilloscope to each sensor in turn although this dosen't always show a duff sensor up, you should
also be able to see the the signal with a good digital multimeter but unless there is no signal at all from one sensor it is likely to be helpful.
Only real way is use a diagnostic scanner --- So it is a garage job or if you want to buy your own I seem to recall the Autel EU702 (about £170 of
eBay) will detect Renault ABS faults -- but check this before buying.
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lsdweb
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| posted on 28/6/11 at 07:30 AM |
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What's the actual fault?
As Britishtrident says, it's strange to have a fault with no warning light!
I'm interested in hearing replies as I have an ABS fault on my Clio but that's probably a damaged front sensor as I couldn't get
them out before rebuilding the front hubs, bearings etc so I may have damaged one!
Wyn
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ss1turbo
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| posted on 28/6/11 at 07:36 AM |
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If you can find a pinout of the ABS ECU, a static resistance test is the easiest IF you suspect a duff sensor. The duff one will be a considerably
different value...but its very odd for an ABS fault with no lamp lit? I assume the lamp comes on with the ignition and goes out a few seconds later
(check without starting the engine just incase someones gone to the effort of bridging it with the oil pressure or alternator lamp - it happens). if
it kicks in far too easily, then its either muck in one of the teeth or otherwise normally an odd sized tyre or even a flat one...
Long live RWD...
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lsdweb
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| posted on 28/6/11 at 07:41 AM |
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The Clio's ABS sensors all have plugs about 18" away from the sensor so easy enough to disconnect to check resistance as ss1turbo
suggests.
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lsdweb
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| posted on 28/6/11 at 08:12 AM |
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I've just measured a new Clio ABS sensor and static resistance is 2.7 kohms. This is off the car.
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ss1turbo
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| posted on 28/6/11 at 08:27 AM |
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I'm glad you came back with a "reference" value as they will be different for differing systems. GM cars tend to be somewhere about
half that from memory.
Long live RWD...
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lsdweb
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| posted on 28/6/11 at 08:31 AM |
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I guess the best option would be for KJ to measure all 4 and see which one (if any) looks odd.
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kj
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| posted on 28/6/11 at 08:31 AM |
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The car drove and was ok before getting a new wheel bearing fitted, the drives ok but when you apply the brakes even at low speed the peddle judders
as if the ABS is kicking in, i have checked on the renault forum and they put it down to the rings on the drive shafts, sensor or disk worn or
distorted, checked the disk and they are ok.
The car we are the second owner and only done 23k.
It looks like a common fault
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ss1turbo
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| posted on 28/6/11 at 08:37 AM |
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For a wheel bearing change, I'm guessing the driveshaft has to come out (or at least it will be undone) which suggests the toothed ring may have
become dislodged/split/missing a tooth. If the pedal judders but the steering wheel doesn't , then its not the disc in my experience.
I'm not au fait with the Clio setup though - does it use a collapsable spacer?
if you had it done by a garage, take it back and tell them they buggered your ABS...the gaffer may well know what the problem is if its a common
issue.
Long live RWD...
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lsdweb
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| posted on 28/6/11 at 10:11 AM |
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Wheel bearing change means driveshaft out and the upright (or lower half) removed to press the bearings out and in. This means there could be damage
to the ABS ring, sensor or wiring, or the wiring plug. I would check that the plug is firmly pushed into the socket first!
The ABS sensors on mine are an absolute bast**d to remove and I left them in when changing the wheel bearings, cleaning the uprights etc so I think
I've damaged one - hence the warning light.
I'm still surprised you have no warning light though!
Wyn
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britishtrident
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| posted on 28/6/11 at 10:16 AM |
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Over the last ten years most manufacturers have changed from ABS reluctor rings to building magnets into the wheel bearings ---- when these were
first fitted it was quite common to get and abs fault if a new front wheel bearing is fitted the wrong way round.
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lsdweb
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| posted on 28/6/11 at 10:49 AM |
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Thinking about it, I'm not sure if the ABS light comes on when the ABS operates so, if you've got a sensor fault or damaged ring, it may
be feeding the ABS ECU some false information and bringing on the ABS.
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britishtrident
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| posted on 28/6/11 at 11:34 AM |
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quote:
Originally posted by lsdweb
Thinking about it, I'm not sure if the ABS light comes on when the ABS operates so, if you've got a sensor fault or damaged ring, it may
be feeding the ABS ECU some false information and bringing on the ABS.
Thinking about it a cracked reluctor ring dosen't always generate a fault light, the ABS control unit just thinks a single wheel has locked.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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adithorp
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| posted on 28/6/11 at 12:28 PM |
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Either, a broken reluctor ring, or if it's a magnetic reluctor in the bearing (don't think the clio is) te bearing is fitted the wrong way
around. Both of those won't put the ABS light on, but a faulty sensor would (normally).
Or it's not the ABS at all and they've got a lot of crap between the disc and hub and thats giving severe brake judder.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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kj
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| posted on 28/6/11 at 01:36 PM |
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Had the sensors out, cleaned and checked the number of teeth on the ring makes it better for a while then back to normal.
I will check the resistance at the week end.
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britishtrident
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| posted on 28/6/11 at 02:54 PM |
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quote:
Originally posted by kj
Had the sensors out, cleaned and checked the number of teeth on the ring makes it better for a while then back to normal.
I will check the resistance at the week end.
All it takes is a crack in a ring.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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lsdweb
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| posted on 11/7/11 at 11:33 AM |
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The new sensor I had is the wrong one!So the 2.7kohms may have not helped! It also has a male connector where the original has a female.
So, I've measured a good sensor on the car - 670 ohms.
I've now fitted a second hand sensor (same resistance) to replace the one that was dead - I think the resistance was infinite - it was seized
and came out in bits so I can't measure it now!
Wyn
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paulf
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| posted on 11/7/11 at 05:45 PM |
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I once fitted a complete front hub assembly and then refitted the original sensor and had the same problem.It turned out that the new hub had a
slightly different sensor mount and the gap between ring and sensor was about 1mm to big it was giving a signal when moving above 20mph but when going
slower the abs was activating.
Paul
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